The provision and control of communication services in mobile networks such as the Public Land Mobile Network (PLMN) are well understood. However, the services that can be provided within the PLMN are restricted to those supported by the Signaling System 7 (SS7) Advanced Intelligent Network (AIN). More importantly, the features supported within any service providers PLMN are restricted to the SS7/AIN feature set licensed by the network provider, which may not be a full implementation of SS7/AIN.
With the advent of deregulation and the introduction of Mobile Virtual Network Operators (MVNO), the rapid and cost-effective introduction of enhanced communications services is desirable. Enhanced communications services are most readily developed and deployed within the flexible environment provided in a hosted Voice over Internet Protocol (VoIP) or an IP Multi-Media Subsystem (IMS) network. Since, inter-working between the PSTN/PLMN and the VoIP/IMS networks is now well supported; services developed in a VoIP/IMS network can now be deployed for use by devices operating in the PLMN.
However, providing those enhanced communications services to PLMN subscribers requires routing control for routing calls placed by enhanced service subscribers to the VoIP/IMS network that supports those services. This poses a problem for MNVOs, as well as for any mobile service provider that supports roaming subscribers. As is well understood by those skilled in the art, normal call routing in the PSTN/PLMN is governed by rigid rules and the dialing plan provisioned within each service provider network. Routing calls along any path other than that dictated by normal call routing in the PLMN requires network provisioning that is frequently impractical or prohibitively expensive to achieve.
There therefore exists a need for a method and system that permits calls to be established in a directed manner that permits enhanced service provision without originating PLMN network provisioning.
Furthermore, it is generally more economical for the service provider and the service subscriber to carry roaming subscriber originated calls over a packet data service to a greatest possible extent. It is therefore in the interest of both parties to pass calls to a most economical gateway in order to reduce call carriage expense.
There therefore exists a need for a method and system that permits calls to be established in the directed manner that reduces the cost of roaming subscriber originated cellular calls.